Cosmogenic 10Be and 26Al dating of erratic boulders in the southern coastal area of Lake Baikal, Siberia

Cosmogenic Be-10 and Al-26 dating of three erratic boulders in the southern coastal area of Lake Baikal was performed using accelerator mass spectrometry (AMS) at MALT (MicroAnalysis Laboratory, Tandem accelerator) of the University of Tokyo. We examined the accuracy of our Be-10 AMS measurements and the differences in scaling factors for the Be-10 and Al-26 production rates. The measured Be-10 and Al-26 ages are 15-13 and 17-11.5 kyr, respectively. The Be-10 ages suggest that release of the erratic boulders from a melting glacier occurred during the Bolling/Allerod warm period, when the land and lacustrine environments of the Baikal region changed dramatically. (C) 2004 Elsevier B.V. All rights reserved.